DESCRIPTION

mkdir()
attempts to create a directory named
pathname.

The argument
mode
specifies the mode for the new directory (see
inode(7)).
It is modified by the process's
umask
in the usual way: in the absence of a default ACL, the mode of the
created directory is
(mode & ~umask & 0777).
Whether other
mode
bits are honored for the created directory depends on the operating system.
For Linux, see NOTES below.

The newly created directory will be owned by the effective user ID of the
process.
If the directory containing the file has the set-group-ID
bit set, or if the filesystem is mounted with BSD group semantics
(mount -o bsdgroups
or, synonymously
mount -o grpid),
the new directory will inherit the group ownership from its parent;
otherwise it will be owned by the effective group ID of the process.

If the parent directory has the set-group-ID bit set, then so will the
newly created directory.

mkdirat()

The
mkdirat()
system call operates in exactly the same way as
mkdir(),
except for the differences described here.

If the pathname given in
pathname
is relative, then it is interpreted relative to the directory
referred to by the file descriptor
dirfd
(rather than relative to the current working directory of
the calling process, as is done by
mkdir()
for a relative pathname).

If
pathname
is relative and
dirfd
is the special value
AT_FDCWD,
then
pathname
is interpreted relative to the current working
directory of the calling process (like
mkdir()).

RETURN VALUE

mkdir()
and
mkdirat()
return zero on success, or -1 if an error occurred (in which case,
errno
is set appropriately).

ERRORS

EACCES

The parent directory does not allow write permission to the process,
or one of the directories in
pathname
did not allow search permission.
(See also
path_resolution(7).)

EDQUOT

The user's quota of disk blocks or inodes on the filesystem has been
exhausted.

EEXIST

pathname
already exists (not necessarily as a directory).
This includes the case where
pathname
is a symbolic link, dangling or not.

EFAULT

pathname points outside your accessible address space.

ELOOP

Too many symbolic links were encountered in resolving
pathname.

EMLINK

The number of links to the parent directory would exceed
LINK_MAX.

ENAMETOOLONG

pathname was too long.

ENOENT

A directory component in
pathname
does not exist or is a dangling symbolic link.

ENOMEM

Insufficient kernel memory was available.

ENOSPC

The device containing
pathname
has no room for the new directory.

ENOSPC

The new directory cannot be created because the user's disk quota is
exhausted.

ENOTDIR

A component used as a directory in
pathname
is not, in fact, a directory.

EPERM

The filesystem containing
pathname
does not support the creation of directories.

EROFS

pathname
refers to a file on a read-only filesystem.

The following additional errors can occur for
mkdirat():

EBADF

dirfd
is not a valid file descriptor.

ENOTDIR

pathname
is relative and
dirfd
is a file descriptor referring to a file other than a directory.

VERSIONS

mkdirat()
was added to Linux in kernel 2.6.16;
library support was added to glibc in version 2.4.

CONFORMING TO

mkdir():
SVr4, BSD, POSIX.1-2001, POSIX.1-2008.

mkdirat():
POSIX.1-2008.

NOTES

Under Linux, apart from the permission bits, the
S_ISVTXmode
bit is also honored.

There are many infelicities in the protocol underlying NFS.
Some of these affect
mkdir().

Glibc notes

On older kernels where
mkdirat()
is unavailable, the glibc wrapper function falls back to the use of
mkdir().
When
pathname
is a relative pathname,
glibc constructs a pathname based on the symbolic link in
/proc/self/fd
that corresponds to the
dirfd
argument.

SEE ALSO

COLOPHON

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man-pages
project.
A description of the project,
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and the latest version of this page,
can be found at
https://www.kernel.org/doc/man-pages/.